Milling cutter pressed from sheet metal



Feb. 9, 1932. K. R. DIENES MILLING CUTTER PRESSED FROM SHEET METAL Filed001: 27, 1930 Iar] Qua 01f pz'enes Patented Feb. 9, 1932 4 UNITED STATESKARL iwnonr mamas, or VILKERATH, GERMANY MILLING CUTTER PBESSE'D FROMSHEET METAL Application filed October 27, 1930, Serial lie. 491,602, andin Germany April 15, 1930.

I have filed applications for this invention in Germany April 15, 1930;in Great Britain October 3, 1930; and in France October 7 1930. .5 Theinvention relates to a special type of milling cutter composed of a discof sheet metal, the periphery being corrugated by a series of foldsrunning from the centre to the rim and pressed alternately from bothsides 10 of the disc, so that when the cutter is ground cylindrically,there are formed at its periphery, cutting edges which are alternatelydisposed to the plane of the milling cutter, and which render itsuitable, when revolved at an appropriate speed about its axis, forworking suitable materials, such as skiving leather, paper or the like.

Hitherto in milling tools made of sheet metal, the recesses forming theperipheral corrugations of the milling cutters ran from the middle flatclamping surface around the central hole towards the edge in a radialdirection, thereby intersecting the peripheral surface at right angles.Thus the cutting edges produced by cylindrical grinding are of rightangled cross-section at each side so that they are relatively blunt andtheir action is more scraping than cutting. Apart from their use forcertain special purposes, the 0 practical value of such tools istherefore relatively small.

According to the present invention, it is possible to give the cuttingedges on these milling tools an acutely sharpened form on one sidewithout altering the simple cylindrical grinding so that when theyrevolve in the direction of this cutting side, they can exert a more orless knife-like. action just like an ordinary milling cutter and aretherefore suitable for the most diverse milling purposes especiallythose requiring high speed cutters. According to the invention, this ismade possible by arranging that the recesses alternately pressed in bothsides of the sheet metal member do not run in a radial straight linetowards the edge of the disc but preferably in a curve running out moreor less tangential at the edge, so that the direction of cut of thecylindrical surface produced by grinding the undulated peripheralrecesses,

is not at a right angle but at a sharp acute angle. The peripheral facesof the sheet metal member produced by this cylindrical grlndmg haveunequal angles at the edge due to the edge nearer thecylinder axishaving 5 an acute form and the edge more remote from this axis an obtuseform. During the rotation of the cutter, the acute edges, when leadlng,therefore act just like the cutting edges of a normal cylindrical facingmill, having the cutt ng edges arranged obliquely or run- ;nng splrallywith respect to the axis of rota? ion.

The cylindrical cutting faces 5 of the sheet metal disc which are madeof undulating 55 shape by pressing in these channels, form acute cuttingangles at the hollow side of the axial bending of the channels or at theedges of the sheet facing the cylinder axis, so that these edges may beused as cutting knives 6. The cutting angle of these edges may, as willbe eas ly seen, be predetermined as desired by fixing the angle of slopeof the channelshaped recesses with respect to the radius or to theperiphery of the plate discs.

For many purposes a more or less large number of these single cuttersmay be comb lled to form a facing mill, as is shown in Fig. 4. Here theindividual cutters 1, are threaded on a milling spindle 7, spaced bydistance rings 8, in such a way that the undulations of their edgesalternately fit into each other. The distance rings, preferably ofunhardened flexible material, such as thick sheet brass, are pressed tothe surface form 86 of the individual cutters themselves, so that thelatter are clamped together not only at their central flat clampingsurface 4, but beyond this over a certain radial distance.

The end rings 9 and 10 situated outside 90 the two outer cutters arepreferably fiat at their external surfaces. As compared with millingcutters of this kind worked from the solid, those pressed from sheetaccording to the present invention are exceedingly simple and cheap tomanufacture.

The invention will be better understood by referring to the accompanyingdrawings.

Fig. 1 being a single cutter according to the invention, partly inelevation viewed 199 from the flat side, line II of Fig. 2,

Fig. 2 a view of the cutter from the edge Fig. 3 a cross-section on lineIII-III of and partly in section on Fig.1 a view partly in sideelevation and partly in axial section of a cylindrlcal facing millcomposed of a large number of separate cutters. v

Fig. 5 is a View looking from the flat s1de of a single flat cutteraccording to-the invention, and iglround in the circumference to anacute pro e.

Fig. 6 shows a cross-section on lme VI-VI of Fig. 5.

The body of the cutter consists of a circular sheet metal disc 1, whichis provided in the middle with a central hole 2 for clam ing the tool tothe milling spindle, the edge 0 the cutter being bent to either side inan undulating or zig-zag shape with respect to the middle plane of thecutter, by channel-shaped recesses 3, pressed into the plate disc fromalternate sides. The channel-shaped recesses 3, commence only at acertain distance from the centering hole, thus leaving a flat annularsurface 4, for clamping the tool on to a mandrel of suitable width. Thechannels themselves preferably follow a circular or spiral course andgradually become deeper towards the edge of the disc which intersectswith the channel at a uniformly acute angle. One of these rings 9, restsagainst a collar 11 on the cutter spindle 7. The end ring is arrangedagainst a clamping nut 12 which together with a lock nut 13, is arrangedon a threaded shoulder 14 of the shaft. By means of the nuts 12 and 13,the cutters 1, may thus be clamped between the rings whilst they areindisplaceably supported by their center holes on the machined surfaceofthe cutter spindle.

As will be seen, all the cutting knives may be sharply ground by acylindrical inding of the cylindrical faces formed by t e edges of themetal disc 1, and whenever they become blunt they can always bere-ground.

For certain kinds of work the peripheral surface of the single cuttersas well as of the combined cutter may have a different profile otherthan a simple cylinder. For instance, as will be seen in Figs. 5. and 6,the individual cutters corresponding to those of Figs. 1-3 have theirsurface not ground cylindrically but conical on each side and with anacute angled or arcuate cross-section.

What I claim is:

1. A milling cutter pressed from sheet metal, particularly for softmaterials, the peripheral portions being alternately bent out withrespect to the middle plane by pressing channel-shaped recesses thereinrunning to the edge, the said peripheral portions acting as cuttingedges set obliquely to the plane of rotation, characterizedin this, thatthe course of the channel-shaped recesses is curved and is so set thatit forms an acute angle with the radii of the cutter disc.

2. A composite cylindrical milling cutter composed of several cutters asin claim 1, characterized in this, that the individual cutters arethreaded on a common millin spindle and are clamped together but spacedapart by annular discs of soft metal with their surface form pressed tosuit that of the cutters.

3. A milling cutter blade consisting of a disc having a convolutedmargin and a substantially at center ortion, the convolutions of themargin exten ing to and mergin into the center along arcuate lineswhereb to form a series of spaced arcuate channel: on each face of thedisc, said channels gradually deepening from the center to the peripheryof the disc and being open at the peripheral ends whereby the peripheraledges of the convolutions form oblique cutting edges.

4. A built up milling cutter consisting of a mandrel, a series ofplastic but strong washers mounted on said mandrel, a series of millingcutter blades mounted on the mandrel alternately with the washers andhaving each a marginal portion and a flat central portion of lessdiameter than the washers, each marginal portion having a convolutedperiphery forming cutting ed es and channels extending from the peripieral convolutions to the flat central portions, and means to force theblades and washers together and embed the marginal portions of thewashers in the inner portions of the channels to secure the bladesagainst rotation with res ect to each other.

In testimony whereof afiix my signature.

' KARL R. DIENES.

